1. Field
Embodiments of the present invention relate to an apparatus for controlling a solenoid valve and a control method thereof, and more particularly, to an apparatus for controlling a solenoid valve, which is capable of reducing an operation noise of the solenoid valve, and a control method thereof.
2. Description of the Related Art
In general, a solenoid valve is installed at each inlet and outlet side of four wheels in a vehicle having an electronically-controlled brake system, e.g., an anti-lock brake system (ABS).
In the ABS vehicle, when a braking force exceeds a friction force between a wheel of the vehicle and a road, and the vehicle starts to be slid, the solenoid valve of the corresponding wheel is operated to reduce a pressure thereof, and then when the vehicle starts to be driven again, the solenoid valve is operated to increase the pressure. Due to such an operation of the ABS, the vehicle is not slid, and is stably braked.
In the electronically-controlled brake system, the solenoid valve serves to supply a brake liquid pressure to a wheel cylinder or to cut off supply of the brake liquid pressure to the wheel cylinder.
The solenoid valve is opened and closed by a current supplied to a solenoid coil.
A conventional solenoid valve controlling device includes a shunt resistance part which detects the current flowing through the solenoid coil in the solenoid valve, a switching part which switches the current flowing through the solenoid coil, a pre-driver which outputs a driving signal to the switching part so as to switch on or off the switching part, and an electronic control unit (ECU) which monitors the current flowing through the solenoid coil using the shunt resistance part and controls the switching part through the pre-driver based on a monitoring result, such that a target current flows through the solenoid coil.
In the conventional solenoid valve controlling device, while the current flowing through the solenoid coil arrives at the target current, the ECU outputs the driving signal having a fixed frequency to the switching part through the pre-driver.
Therefore, an acoustic noise having the same frequency is generated at a solenoid valve assembly.